The angle between the magnetic meridian and geographical meridian is called

Isogonic lines on a magnetic map will have

The angle of dip at a certain place is $30^o$. If the horizontal component of the earth's magnetic field is $H$,the intensity of the total magnetic field is:

The lines joining the places of the same horizontal intensity are known as

At a certain place,the vertical component of the Earth's magnetic field is $\sqrt{3}$ times the horizontal component of the Earth's magnetic field. If a magnetic needle is suspended freely in the air,then it will incline:

Give information about Earth's magnetism.